THE LIFE OF MAMMALS 
phants. It was of gigantic size, perhaps eighteen feet long, for the skull 
measures a yard fore and aft. The structure of the teeth resembles that 
of the teeth of tapirs; but from the elongated and downward-bent lower 
jaw grew two long incisor-tusks unlike anything else known in animal 
dentition. ‘‘The enormous weight of the Jower jaw and tusks seems to 
argue that it was at least partially aquatic in habit, and that it may have 
used these tusks for grubbing up aquatic 
roots or for mooring itself to the bank.” 
Such has been the history of the 
noble but decadent elephant family. 
Its nearest living ally, as has been 
said (page 232), is the quaint little 
cony of the order Hyracoidea. The 
origin of the elephants had not until 
recently been traced, but that they 
were an offshoot from the primitive 
saa ec are condylarths could not be doubted. 
of the lower jay Professor H. F. Osborn stated in 
were probably used 
in raking up roots 1900 that the early ancestors of 
from the mud of the Proboscidea would probably be 
rivers and lakes. 
found in the then unexplored Eo- 
cene formations of Africa. This prediction was realized in 
1902, when Dr. Andrews examined this formation in Egypt 
for the British Museum, and obtained fossil evidence con- 
necting the elephants with the primitive hoofed animals, and 
showing the successive stages by which the huge grinding- 
African teeth, tusks, and trunk were gradually developed. 
Ong A brief review of the history of the family in the 
light of these new facts will be useful. 
DINOTHERIUM. 
The series begins in the Middle Eocene with Moerotherium, an animal 
of moderate size, with a full set of tapirlike teeth, no trunk, and no tusks, 
but the middle incisor teeth enlarged in both jaws. In Paleomastodon of 
the Upper Eocene, the incisors are reduced to a pair of small tusks in each 
jaw, there is a short trunk, and the back grinders are becoming larger, 
while the fore ones are degenerating. In the Miocene Dinotherium (a 
392 
